OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
FORMULA
From Wesley Ivan Hurt, Jun 09 2016: (Start)
G.f.: x^2*(4+x+3*x^2)/((x-1)^2*(1+x+x^2)).
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-21-6*cos(2*n*Pi/3)-4*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-3, a(3k-1) = 8k-4, a(3k-2) = 8k-8. (End)
MAPLE
A047609:=n->(24*n-21-6*cos(2*n*Pi/3)-4*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047609(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{0, 4, 5}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [0, 4, 5]]; // Wesley Ivan Hurt, Jun 09 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved